1. Field of the Invention
This invention relates in general to a fuel delivery system, and more in particular, to fuel pump control in a mechanical returnless fuel system.
2. Description of the Related Art
Inertia switches are commonly used in vehicles to disable the fuel pump in the event of a severe vehicle crash. The inertia switch is similar to a relay that the inertia switch includes a first contact for receiving power and a second contact for outputting power to the fuel pump motor. As opposed to an electric solenoid coil or some thermal expansion device required to break the power feed circuit, the inertia switch uses a mechanical element consisting of a steel ball in a funnel. The steel ball is held in place by a magnet disposed in the bottom of the funnel. When the vehicle is subjected to impacts or vehicle roll, the steel ball will break free from the magnet and roll up the funnel. At the top of the funnel is an arm switch mechanism. As the steel ball approaches the top of the funnel, the steel ball contacts the arm switch mechanism thereby opening the circuit and disconnecting power to the fuel pump. A disadvantage with the inertia switch is that proper calibration and packaging of the inertia switch is becoming increasingly difficult due to the characteristics of current vehicle structures.
The inertia switch is a stand-alone component that is separate from current production vehicle impact sensing systems which sense vehicle impacts and provide safety countermeasures such as airbag deployment and other safety measures. It would be advantageous to replace the inertia switch without the expense if applying an additional system. The replacement unit for the inertia switch must also be reliable in sensing and determining a vehicle impact and also be compatible with the current fuel delivery system such that it would not interfere with fuel delivery system in its normal operating state but only intervene in the event of a vehicle impact.
What would be advantageous is to have a system that may be utilized without changing the current architecture of the fuel delivery system but have benefits of use with the vehicle impact sensing, notification, and fuel control operations.